h) a sulfamoyl group which is unsubstituted or substituted on nitrogen by one or two C.sub.1 -C.sub.4 alkyl groups: ##STR50## where R.sup.y and R.sup.z are as defined above; i) an amino group, or a mono (C.sub.1 -C.sub.4 alkyl) amino ordi(C.sub.1 -C.sub.4 alkyl)-amino group: ##STR51## where R.sup.y and R.sup.z are as defined above; j) a formylamino group: ##STR52## k) (C.sub.1 -C.sub.6 alkyl)carbonylamino radical: ##STR53## alkyl; l) a (C.sub.1 -C.sub.4 alkoxy) carbonylamino radical:##STR54## alkyl; m) a ureido group in which the terminal nitrogen is unsubstituted or substituted with one or two C.sub.1 -C.sub.4 alkyl groups: ##STR55## where R.sup.y and R.sup.z are as defined above; n) a sulfonamido group: ##STR56## alkyl; o) acyano group: --CN;

p) a formyl or acetalized formyl radical: ##STR57## q) (C.sub.1 -.sub.6 alkyl)carbonyl radical wherein the carbonyl is free or acetalized: ##STR58## alkyl or ##STR59## alkyl; s) a hydroximinomethyl radical in which the oxygen or carbon atom isoptionally substituted by a C.sub.1 -C.sub.4 alkyl group: ##STR60## where R.sup.y and R.sup.z are as defined above; t) a (C.sub.1 -C.sub.6 alkoxy)carbonyl radical: ##STR61## alkyl; u) a carbamoyl radical which is unsubstituted or substituted onnitrogen by one or two C.sub.1 -C.sub.4 alkyl groups: ##STR62## where R.sup.y and R.sup.z are as defined above; v) an N-hydroxycarbamoyl or N(C.sub.1 -C.sub.4 alkoxy)carbamoyl radical in which the nitrogen atom may be additionally substituted by aC.sub.1 -C.sub.4 alkyl group: ##STR63## where R.sup.y and R.sup.z are as defined above; w) a thiocarbamoyl group: ##STR64## x) an amidino group ##STR65## where R.sup.5, R.sup.6 and R.sup.7 are independently hydrogen, C.sub.1 -C.sub.4 alkyl or whereintwo of the alkyl groups together form a C.sub.2 -C.sub.6 alkylidene radical optionally interrupted by a heteroatom and joined together to form a ring;

y) a carboxamidino group ##STR66## where R.sup.5, R.sup.6 and R.sup.7 are as defined above; z) a guanidinyl group where R.sup.6 in a) above is NR.sup.8 R.sup.9 and R.sup.8 and R.sup.9 are as defined for R.sup.5 through R.sup.7 above;

aa) hydrogen;

ab) C.sub.2 -C.sub.6 alkenyl radical;

ac) an unsubstituted or substituted C.sub.2 -C.sub.6 alkynyl radical;

ad) C.sub.3 -C.sub.7 cycloalkyl radical;

ae) C.sub.3 -C.sub.7 cycloalkyl methyl radical;

af) C.sub.5 -C.sub.7 cycloalkenyl radical;

ag) phenyl;

ah) C.sub.1 -C.sub.6 alkyl radical;

ai) C.sub.1 -C.sub.4 alkyl monosubstituted by one of the substituents a)-ag) above;

R.sup.x is phenyl or heteroaryl, where heteroaryl is as defined below except that there is no quaternary nitrogen and attachment through nitrogen is optional, and the phenyl and heteroaryl are optionally mono-substituted by R.sup.q ; M.sup.c ishydrogen or an alkali metal; R.sup.y and R.sup.z are as defined above; where

A is para (p) or meta (m) with respect to the point of attachment of the phenyl ring to the carbapenem nucleus, and is (CH.sub.2).sub.m --Q--(CH.sub.2).sub.n, where m is 0 to 2 and n is 1 or 2; and Q is a covalent bond; O; S; SO; SO.sub.2 ; NH; or N(C.sub.1 -C.sub.4 alkyl); ##STR67## is a monocyclic aromatic hydrocarbon group having 5 or 6 ring atoms in which one of the carbon atoms has been replaced by a nitrogen atom and attachment of said group is by way of said nitrogen atom, and inwhich one additional carbon atom is optionally replaced by a heteroatom selected from O and S, and from 1 to 3 carbon atoms are optionally replaced by a nitrogen heteroatom; and ##STR68## is a monocyclic aliphatic hydrocarbon group having 4 to 7 ringatoms in which one of the carbon ring atoms is replaced by a nitrogen atom and attachment of said group is by way of said nitrogen atom to a carbon of the monocyclic aromatic hydrocarbon group described above, and one of the remaining carbon ring atomsis optionally replaced by a heteroatom selected from N, O and S; and wherein the substitutent R.sup.d, defined above, is attached to one of the carbon atoms of the ring; and

Y is selected from:

i) COOH or a pharmaceutically acceptable ester thereof;

ii) COOM wherein M is an alkali metal or other pharmaceutically acceptable salt;

iii) COOM wherein M is a negative charge in the case where a permanent positive charge exists elsewhere in the molecule.

2. A compound according to claim 1 wherein R.sup.1 /R.sup.2 is H-- and R.sup.2 /R.sup.1 is CH.sub.3 CH(OH)--.

3. A compound according to claim 1 wherein R.sup.1 /R.sup.2 is H-- and R.sup.2 /R.sup.1 is CH.sub.3 CH(OH)--; and A is --CH.sub.2 --.

4. A compound according to claim 1 wherein R.sup.1 /R.sup.2 is H-- and R.sup.2 /R.sup.1 is CH.sub.3 CH(OH)--; A is --CH.sub.2 --; and ##STR69## is selected from the group consisting of ##STR70## where X=O, S, or NR.sup.e, where R.sup.e=C.sub.1-4 alkyl, CH.sub.2 SO.sub.3.sup.-, CH.sub.2 CH.sub.2 SO.sub.3.sup.-, or CH.sub.2 COR.sup.f, where R.sup.f =OCH.sub.3, OCH.sub.2 -phenyl, NH.sub.2, or O.sup.- M.sup.+, where M.sup.+ =Na.sup.+ or K.sup.+.

5. A compound according to claim 1 wherein R.sup.1 /R.sup.2 is H-- and R.sup.2 /R.sup.1 is CH.sub.3 CH(OH)--; A is ##STR71##

6. A compound according to claim 1 wherein R.sup.1 /R.sup.2 is H-- nd R.sup.2 /R.sup.1 is CH.sub.3 CH(OH)--; A is ##STR72## is selected from ##STR73##

7. A compound according to claim 1 wherein the compound is selected from the group consisting of ##STR74## where R' is a negative charge .sup.-, a pharmaceutically acceptable ester, or additionally a readily removable carboxyl covering groupwhich is not a pharmaceutically acceptable ester.

8. A pharmaceutical composition for antibacterial use comprising an antibacterially effective amount of a compound of claim 1 and a pharmaceutically acceptable carrier therefor.

9. A method of treating bacterial infections in human or animal subjects in need of such treatment comprising administering to such subject an antibacterially effective amount of a compound of claim 1.

10. The combination of a compound of claim 1 and a DHP inhibitor.

11. The combination of a compound of claim 7 and the DHP inhibitor 7-(L-2-amino-2-carboxyethylthio)-2-( 2,2-dimethylcyclopropanecarboxamide)-2-heptenoic acid.

12. A pharmaceutical composition for antibacterial use comprising an antibacterially effective amount of a compound of claim 1, an inhibitorily effective amount of a DHP inhibitor, and, optionally, a pharmaceutically acceptable carrier therefor.

13. A pharmaceutical composition according to claim 12 wherein the DHP inhibitor is 7-(L-2-amino-2-carboxyethylthio)-2-(2,2-dimethylcyclopropanecarboxamide)-2 -heptenoic acid.

14. A method of treating bacterial infections in human or animal subjects in need of such treatment comprising coadministering to such subject an antibacterially effective amount of a compound of claim 1 and an inhibitorily effective amount of aDHP inhibitor.

15. A method according to claim 14 wherein the DHP inhibitor is 7-(L-2-amino-2-carboxyethylthio)-2-(2,2-dimethylcyclopropanecarboxamide)-2 -heptenoic acid.

Description:

BACKGROUND OF THE INVENTION

The present invention relates to antibacterial agents of the carbapenem class, in which the 2-position sidechain is characterized by a phenyl moiety, optionally substituted, to which is attached, usually through an alkyl bridge, anitrogen-containing heteroarylium group, with attachment being through the nitrogen atom, to which is attached, in turn, a heterocyclic group, as described in more detail further below.

Thienamycin was an early carbapenem antibacterial agent having a broad spectrum; it has the following formula: ##STR2## Later, N-formimidoyl thienamycin was discovered; it has the formula: ##STR3##

The 2-(heterocyclylheteroaryliumalkyl)phenyl carbapenems of the present invention have an antibacterial potency equal to or greater than, in most cases, that of either thienamycin or N-formimidoyl thienamycin. The compounds of the presentinvention are also more resistant than thienamycin or N-formimidoyl thienamycin to degradation by the dehydropeptidase enzyme DHP-I, thus permitting greater therapeutic application of the compounds.

More recently, carbapenem antibacterial agents have been described which have a 2-substituent which is an aryl moiety optionally substituted by, e.g., aminomethyl and substituted aminomethyl. These agents are described in U.S. Pat. Nos. 4,543,257 and 4,260,627 and have the formula: ##STR4##

However, these compounds belong to a different class from those of the present invention and are distinguished by different physiological properties.

h) a sulfamoyl group which is unsubstituted or substituted on nitrogen by one or two C.sub.1 -C.sub.4 alkyl groups: ##STR9## where R.sup.y and R.sup.z are as defined above; i) an amino group, or a mono (C.sub.1 -C.sub.4 alkyl) amino or di(C.sub.1-C.sub.4 alkyl)amino group: ##STR10## where R.sup.y and R.sup.z are as defined above; j) a formylamino group: ##STR11## k) (C.sub.1 -C.sub.6 alkyl)carbonylamino radical: ##STR12## alkyl; l) a (C.sub.1 -C.sub.4 alkoxy)carbonylamino radical: ##STR13##alkyl; m) a ureido group in which the terminal nitrogen is unsubstituted or substituted with one or two C.sub.1 -C.sub.4 alkyl groups: ##STR14## where R.sup.y and R.sup.z are as defined above; n) a sulfonamido group: ##STR15## alkyl; o) a cyano group:--CN;

s) a hydroximinomethyl radical in which the oxygen or carbon atom is optionally substituted by a C.sub.1 -C.sub.4 alkyl group: ##STR19## where R.sup.y and R.sup.z are as defined above; t) a (C.sub.1 -C.sub.6 alkoxy)carbonyl radical: ##STR20##alkyl; u) a carbamoyl radical which is unsubstituted or substituted on nitrogen by one or two C.sub.1 -C.sub.4 alkyl groups: ##STR21## R.sup.y and R.sup.z are as defined above; v) an N-hydroxycarbamoyl or N(C.sub.1 -C.sub.4 alkoxy)carbamoyl radical inwhich the nitrogen atom may be additionally substituted by a C.sub.1 -C.sub.4 alkyl group: ##STR22## where R.sup.y and R.sup.z are as defined above; w) a thiocarbamoyl group: ##STR23## x) an amidino group ##STR24## where R.sup.5, R.sup.6 and R.sup.7 areindependently hydrogen, C.sub.1 -C.sub.4 alkyl or wherein two of the alkyl groups together form a C.sub.2 -C.sub.6 alkylidene radical optionally interrupted by a heteroatom and joined together to form a ring;

y) a carboxamidino group ##STR25## where R.sup.5, R.sup.6 and R.sup.7 are as defined above; z) a guanidinyl group where R.sup.6 in a) above is NR.sup.8 R.sup.9 and R.sup.8 and R.sup.9 are as defined for R.sup.5 through R.sup.7 above;

aa) hydrogen;

ab) C.sub.2 -C.sub.6 alkenyl radical;

ac) an unsubstituted or substituted C.sub.2 -C.sub.6 alkynyl radical;

ad) C.sub.3 -C.sub.7 cycloalkyl radical;

ae) C.sub.3 -C.sub.7 cycloalkyl methyl radical;

af) C.sub.5 -C.sub.7 cycloalkenyl radical;

ag) phenyl;

ah) C.sub.1 -C.sub.6 alkyl radical;

ai) C.sub.1 -C.sub.4 alkyl monosubstituted by one of the substituents a)-ag) above;

R.sup.x is phenyl or heteroaryl, where heteroaryl is as defined below except that there is no quaternary nitrogen and attachment through nitrogen is optional, and the phenyl and heteroaryl are optionally mono-substituted by R.sup.q ; M.sup.c ishydrogen or an alkali metal; R.sup.y and R.sup.z are as defined above; where

A is para (p) or meta (m) with respect to the point of attachment of the phenyl ring to the carbapenem nucleus, and is (CH.sub.2).sub.m --Q--(CH.sub.2).sub.n, where m is 0 to 2 and n is 1 or 2; and Q is a covalent bond; O; S; SO; SO.sub.2 ; NH;or N(C.sub.1 -C.sub.4 alkyl); ##STR26## is a monocyclic aromatic hydrocarbon group having 5 or 6 ring atoms in which one of the carbon atoms has been replaced by a nitrogen atom and attachment of said group is by way of said nitrogen atom, and in whichone additional carbon atom is optionally replaced by a heteroatom selected from O and S, and from 1 to 3 carbon atoms are optionally replaced by a nitrogen heteroatom; and ##STR27## is a monocyclic aliphatic hydrocarbon group having 4 to 7 ring atoms inwhich one of the carbon ring atoms is replaced by a nitrogen atom and attachment of said group is by way of said nitrogen atom to a carbon of the monocyclic aromatic hydrocarbon group described above, and one of the remaining carbon ring atoms isoptionally replaced by a heteroatom selected from N, O and S; and wherein the substituent R.sup.d, defined above, is attached to one of the carbon atoms of the ring; and

Y is selected from:

i) COOH or a pharmaceutically acceptable ester thereof;

ii) COOM wherein M is an alkali metal or other pharmaceutically acceptable salt;

iii) COOM wherein M is a negative charge in the case where a permanent positive charge exists elsewhere in the molecule.

The R.sup.c.sub.(1-3) substituent represents from 1 to 3 substituents which may be the same or different and are selected on an independent basis. A single such substituent is preferred.

The overall molecule must be electronically balanced. Since a quaternary nitrogen is always present in the compounds of the present invention, a balancing anion must also be present. This is usually accomplished by having Y be COO.sup.-. However, where Y is, e.g., a pharmaceutically acceptable ester, a counterion (anion) Z.sup.- must be provided, or alternatively, an anionic substituent might be utilized. Further, it is within the scope of this invention to utilize an anionicsubstituent where the quaternary nitrogen is already balanced by Y.dbd.COO.sup.-. In that case, it will be understood that it is necessary to provide a counterion (cation) for the anionic substituent. However, it is well within the skill of a medicinalchemist, to whom there is available many suitable anionic and cationic counterions, to make such choices.

With reference to the above definitions, "alkyl" means a straight or branched chain aliphatic hydrocarbon radical.

The term "heteroatom" means N, S, or O, selected on an independent basis.

Under the definition of "Y", the term "pharmaceutically acceptable ester or salt" refers to those salt and ester forms of the compounds of the present invention which would be apparent to the pharmaceutical chemist, i.e., those which arenon-toxic and which would favorably affect the pharmacokinetic properties of said compounds, their palatability, absorption, distribution, metabolism and excretion. Other factors, more practical in nature, which are also important in the selection, arecost of raw materials, ease of crystallization, yield, stability, hygroscopicity, and flowability of the resulting bulk drug. Since the compounds of the present invention may be carboxylates, the salts would be cations such as benzathine,chloroprocaine, choline, diethanolamine, meglumine and procaine. The metallic cations such as aluminum, calcium, lithium, magnesium and zinc are potential choices. The alkali metal cations sodium and potassium are specifically defined. It will also benoted that the compounds of the present invention are potentially internal salts or zwitterions, since under physiological conditions the carboxyl group may be anionic, and this electronic charge will be balanced off internally against the cationiccharge of the heteroarylium group. Where this is not the case, it is recognized that a counterion must be present. This counterion is selected from the group of suitable pharmaceutical anions, e.g., chloride, phosphate and tartrate.

It is preferred that when one of R.sup.1 or R.sup.2 is H, the other is (R)--CH.sub.3 CH(OH)-- or (R)--CH.sub.3 CH(F)--, and (R)--CH.sub.3 CH(OH)-- is most preferred. Further, it is preferred that the configuration at C-6 is (S), and that at C-5is (R).

Representative R.sup.c and R.sup.d groups are --CH.sub.3, ##STR28## Useful examples of the heteroarylium moiety are set out below. The heteroarylium moiety has been conveniently represented throughout by the following formula: ##STR29## whereX=O, S, or NR.sup.e, where R.sup.e =C.sub.1-4 alkyl, CH.sub.2 SO.sub.3.sup.-, CH.sub.2 CH.sub.2 SO.sub.2.sup.-, or CH.sub.2 COR.sup. f, where R.sup.f =OCH.sub.3, OCH.sub.2 -phenyl, NH.sub.2, or O.sup.- M.sup.+, where M.sup.+ =Na.sup.+ or K.sup.+.

The pyridinium group is preferred since it provides the desired properties of good antibacterial spectrum and potency combined with chemical stability and satisfactory resistance to hydrolysis by the dihydropeptidase (DHP-I) enzyme, together withready availability and ease of handling as a starting material. However, any of the other groups set out above, as well as those falling within the definition of the heteroarylium moiety set out herein but not specifically described above, are alsosuitable, although perhaps in some cases less desirable in terms of one or more of the criteria mentioned above.

Representative examples of the heterocyclyl moiety are set out below. ##STR30## With regard to all of the preferred substituents described above, the following compounds are preferred embodiments of the present invention: ##STR31## where R' is anegative charge .sup.-, or a pharmaceutically acceptable salt or ester.

While R=H is usually preferred, there are instances in which R=CH.sub.3 may provide improved chemical stability, water solubility, or pharmacokinetic behavior. The substituent R=CH.sub.3 may be of either configuration, i.e., the .alpha. or.beta.-stereoisomer.

For most of the compounds exemplified herein, the R substituent is hydrogen. This is the result not only of a more facile synthesis for such compounds, but also of a preference for R=hydrogen based on the superior antibacterial activity of suchcompounds.

The carbapenem compounds of the present invention are useful per se and in their pharmaceutically acceptable salt and ester forms in the treatment of bacterial infections in animal and human subjects. Conveniently, pharmaceutical compositionsmay be prepared from the active ingredients in combination with pharmaceutically acceptable carriers. Thus, the present invention is also concerned with pharmaceutical compositions and methods of treating bacterial infections utilizing as an activeingredient the novel carbapenem compounds of the present invention.

The pharmaceutically acceptable salts referred to above include non-toxic acid addition salts. In those cases where the Formula I compounds possess a basic functional group, they can be used in the form of salts derived from inorganic or organicacids. Included among such salts are the following: acetate, adipate, alginate, aspartate, benzoate, benzenesulfonate, bisulfate, butyrate, citrate, camphorate, camphorsulfonate, cyclopentanepropionate, digluconate, dodecylsulfate, ethanesulfonate,fumarate, glucoheptanoate, glycerophosphate, hemisulfate, heptanoate, hexanoate, hydrochloride, hydrobromide, hydroiodide, 2-hydroxyethanesulfonate, lactate, maleate, methanesulfonate, 2-naphthalenesulfonate, nicotinate, oxalate, pamoate, pectinate,persulfate, 3-phenylpropionate, picrate, pivalate, propionate, succinate, tartrate, thiocyanate, tosylate, and undecanoate. Also, the basic nitrogen-containing groups can be quaternized with such agents as lower alkyl halides, such as methyl, ethyl,propyl, and butyl chloride, bromides and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl; and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides like benzyl andphenethyl bromides and others. Water or oil-soluble or dispersible products are thereby obtained.

The pharmaceutically acceptable esters of the novel carbapenem compounds of the present invention are such as would be readily apparent to a medicinal chemist, and include, for example, those described in detail in U.S. Pat. No. 4,309,438,Column 9, line 61 to Column 12, line 51, which is incorporated herein by reference. Included within such pharmaceutically acceptable esters are those which are hydrolyzed under physiological conditions, such as pivaloyloxymethyl, acetoxymethyl,phthalidyl, indanyl and methoxymethyl, and those described in detail in U.S. Pat. No. 4,479,947, which is incorporated herein by reference.

The compounds of the present invention are valuable antibacterial agents active against various Gram-positive and Gram-negative bacteria and accordingly find utility in human and veterinary medicine. Representative pathogens which are sensitiveto the antibacterial agents of the present invention include various species or strains of the following: Staphylococcus, Enterococcus, Escherichia coli, Klebsiella, Enterobacter, Bacillus, Salmonella, Pseudomonas, Serratia, Proteus, and Bacterium. Theantibacterials of the invention are not limited to utility as medicaments; they may be used in all manner of industry, for example: additives to animal feed, preservation of food, disinfectants, and in other industrial systems where control of bacterialgrowth is desired. For example, they may be employed in aqueous compositions in concentrations ranging from 0.1 to 100 parts of antibiotic per million parts of solution in order to destroy or inhibit the growth of harmful bacteria on medical and dentalequipment and as bactericides in industrial applications, for example in waterbased paints and in the white water of paper mills to inhibit the growth of harmful bacteria.

The compounds of this invention may be used in any of a variety of pharmaceutical preparations. They may be employed in capsule, powder form, in liquid solution, or in suspension. They may be administered by a variety of means; those ofprincipal interest include: topically or parenterally by injection (intravenously or intramuscularly).

Compositions for injection, a preferred route of delivery, may be prepared in unit dosage form in ampules, or in multidose containers. The compositions may take such forms as suspensions, solutions, or emulsions in oily or aqueous vehicles, andmay contain formulatory agents. Alternatively, the active ingredient may be in powder form for reconstitution, at the time of delivery, with a suitable vehicle, such as sterile water. Topical applications may be formulated in hydrophobic or hydrophilicbases as ointments, creams, lotions, paints, or powders.

The dosage to be administered depends to a large extent upon the condition and size of the subject being treated as well as the route and frequency of administration, the parenteral route by injection being preferred for generalized infections. Such matters, however, are left to the routine discretion of the therapist according to principles of treatment well known in the antibacterial art. In general, a daily dosage consists of from about 5 to about 600 mg of active ingredient per kg of bodyweight of the subject in one or more treatments per day. A preferred daily dosage for adult humans lies in the range of from about 10 to 240 mg of active ingredient per kg of body weight. Another factor influencing the precise dosage regimen, apartfrom the nature of the infection and peculiar identity of the individual being treated, is the molecular weight of the chosen species of this invention.

The compositions for human delivery per unit dosage, whether liquid or solid, may contain from 0.1% to 99% of active material, the preferred range being from about 10-60%. The composition will generally contain from about 15 mg to about 1500 mgof the active ingredient; however, in general, it is preferable to employ a dosage amount in the range of from about 250 mg to 1000 mg. In parenteral administration, the unit dosage is usually the pure compound I in sterile water solution or in the formof a soluble powder intended for solution.

The preferred method of administration of the Formula I antibacterial compounds is parenteral by i.v. infusion, i.v. bolus, or i.m. injection.

For adults, 5-50 mg of Formula I antibacterial compounds per kg of body weight given 2, 3, or 4 times per day is preferred. Preferred dosage is 250 mg to 1000 mg of the Formula I antibacterial given two (b.i.d.) three (t.i.d.) or four (q.i.d.)times per day. More specifically, for mild infections, and particularly urinary tract infections, a dose of 250 mg t.i.d. or q.i.d. is recommended. For moderate infections against highly susceptible gram positive and gram negative organisms, a doseof 500 mg t.i.d. or q.i.d. is recommended. For severe, life-threatening infections against organisms at the upper limits of sensitivity to the antibiotic, a dose of 1000 mg t.i.d. or q.i.d. is recommended.

For children, a dose of 5-25 mg/kg of body weight given 2, 3, or 4 times per day is preferred; a dose of 10 mg/kg t.i.d. or q.i.d. is usually recommended.

Antibacterial compounds of Formula I are of the broad class known as carbapenems or 1-carbadethiapenems. Naturally occurring carbapenems are susceptible to attack by a renal enzyme known as dehydropeptidase (DHP). This attack or degradation mayreduce the efficacy of the carbapenem antibacterial agent. The compounds of the present invention, on the other hand, are significantly less subject to such attack, and therefore may not require use of a DHP inhibitor. However, such use is optional andcontemplated to be a part of the present invention. Inhibitors of DHP and their use with carbapenem antibacterial agents are disclosed in the prior art [see European Patent Applications No. 79102616.4 filed Jul. 24, 1979 (Patent No. 0 010 573);79102615.6, filed Jul. 24, 1979 (Patent No. 0 007 614); and No. 82107174.3, filed Aug. 9, 1982 (Publication No. 0 072 014)].

The compounds of the present invention may, where DHP inhibition is desired or necessary, be combined or used with the appropriate DHP inhibitor as described in the aforesaid patents and published application. Thus, to the extent that the citedEuropean patent applications 1.) define the procedure for determining DHP susceptibility of the present carbapenems and 2.) disclose suitable inhibitors, combination compositions and methods of treatment, they are incorporated herein by reference. Apreferred weight ratio of Formula I compound:DHP inhibitor in the combination compositions is about 1:1. A preferred DHP inhibitor is 7-(L-2-amino-2-carboxyethylthio)-2-(2,2-dimethylcyclopropanecarboxamide)-a cid or a useful salt thereof.

These combination compositions and their use are further embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The 2-(heterocyclylheteroaryliumalkyl)phenyl carbapenem compounds of the present invention may be prepared in accordance with well known procedures in the art. Particularly useful are the following synthetic schemes in which the various symbolsemployed are as defined above. ##STR32##

The steps for preparing the 2-phenyl carbapenem intermediate are well known in the art and are explained in ample detail in U.S. Pat. Nos. 4,260,627 and 4,543,257, which are incorporated herein by reference. Addition of thehetercyclylheteroaryliumalkyl moiety, generally represented by the formula: ##STR33## is as represented in the schematic diagram above.

The bridging element "A" is already in place when the phenyl group becomes a part of the carbapenem compound at the time of cyclization. In the preferred embodiments of the present invention, the bridging element "A" is simply alkyl. However,it is also an embodiment of the present invention to include a heteroatom in the alkyl chain, as defined further above. Preparation of such a heteroatom-containing alkyl bridge is in accordance with the following synthetic scheme: ##STR34##

The bridging element terminates in a hydroxyl group which is then changed to an active leaving group, e.g., iodide. Treatment with the desired heterocyclylheteroaryl reactant directly provides the heterocyclylheteroaryliumalkylphenyl sidechain. More particularly, three alternative procedures may be utilized for addition of the heterocyclylheteroarylium group.

Activation of the Phenyl-A-OH Group

This step may be carried out in accordance with well-known procedures, some of which are exemplified in the following equations. ##STR35##

In words relative to the equations, the hydroxyl group may be converted to a methanesulfonate group by treating with methanesulfonyl chloride in the presence of triethylamine. A suitable solvent, e.g., dichloromethane, is employed and thereaction is carried out at reduced temperatures. In turn, the methanesulfonate intermediate may be converted to the more reactive iodide derivative by treatment with sodium iodide in a suitable solvent, e.g., acetone, at reduced or ambient temperatures. Alternatively, the hydroxyl group may be directly converted into the iodide group by common methods known in the art. For example, treatment of the hydroxyl group with methyl triphenoxyphosphonium iodide in a suitable solvent, such as dimethylformamide,at reduced or ambient temperatures, directly provides the desired iodide. Further, the hydroxyl group may be converted into the very reactive trifluoromethanesulfonate group. However, such an activating group cannot be isolated by conventionaltechniques but may be formed and used in situ. Thus, treatment of the hydroxyl group with trifluoromethanesulfonic acid anhydride in the presence of, usually, the reacting heterocyclylheteroaromatic base in a suitable solvent, such as dichloromethane,at reduced temperatures provides for the in situ generation of this activating group. Alternatively, the trifluoromethanesulfonate group may be generated in situ from the iodide group by treatment with excess silver trifluoromethanesulfonate in asuitable solvent, e.g., acetonitrile, at reduced temperatures.

Once the desired activation has been carried out, introduction of the heterocyclylheteroarylium group can then proceed. One of the following three procedures has been found suitable for such introduction.

Method A

The activated group is iodide and the addition of the heterocyclylheteroarylium group, e.g., 4-N-thiamorpholinylpyridinium, is accomplished simply by treating with the corresponding heteroaryl, e.g., 4-N-thiamorpholinylpyridine, in a suitablesolvent, e.g., acetonitrile, at about room temperature.

Method B

The activating group is trifluoromethanesulfonate and is formed in situ by treatment of the alcohol with trifluoromethanesulfonic acid anhydride in the presence of at least two equivalents of heterocyclylheteroaryl to provide the correspondingheterocyclylheteroarylium in a suitable solvent, e.g., dichloromethane, at reduced temperatures.

Method C

The activated group is trifluoromethanesulfonate which is formed in situ by treatment of the iodide derivative with excess silver trifluoromethanesulfonate in a suitable solvent, e.g., acetonitrile, at reduced temperatures. As with Method A, theheterocyclylheteroaryl to provide the corresponding heterocyclylheteroarylium is simply added and displacement of the activating group then takes place directly.

Where the heterocyclylheteroarylium group has one or more substituents R.sup.c and R.sup.d, the most facile method of providing such a substituent is to employ as the reactant in the preparation methods described above a heterocyclylheteroarylcompound which already has the desired substituent(s). Such substituted heterocyclylheteroaryl compounds are readily available starting materials or may be prepared in a straight-forward manner using known literature methods.

In the preparation methods described above, the carboxyl group at the 3-position remains blocked by a carboxyl covering group until the final product is prepared. Then, if the anionic carboxylate is desired so as to form the zwitterionicinternal salt, deblocking may be carried out in a conventional manner, with care being taken to avoid a procedure which is so harsh as to disrupt other portions of the final product molecule.

The general synthesis description above and the particular exemplifications which follow show the 6-(1-hydroxyethyl) moiety, which is preferred in most cases. However, it has been found that with certain 2-sidechain selections, the ultimatebalance of favorable clinical properties in the overall molecule may be enhanced by selection of the 6-(1-fluoroethyl) moiety instead. Preparation of this and other 6-fluoroalkyl compounds within the scope of the present invention may be carried out ina straightforward manner using techniques well known in the art of preparing carbapenem antibacterial compounds. See, e.g., J. G. deVries et al., Heterocycles, 23 (8), 1915 (1985); J6-0163- 882-A (Sanraku Ocean).

For all of the compounds exemplified herein, the R substituent is hydrogen, which is preferred. However, when R=methyl, the analogous 6-(1-hydroxyethyl) and 6-(1-fluoroethyl)carbapenems of the present invention are prepared in the mannerdescribed herein utilizing the appropriately chosen synthons which are known in the art. See, for example, L. M. Fuentes, I. Shinkai, and T. N. Salzmann, JACS, 108, 4675 (1986); and BE-900-718-A (Sandoz) respectively.

In 5 ml of sieve dried acetonitrile (CH.sub.3 CN) there was dissolved enantiomerically pure 2-(iodomethyl-4-phenyl)carbapenem (3.) (166.3 mg, 0.310 mmole), and the solution was cooled to 0.degree. C. There was then added neat4-pyrrolidinopyridine (4.) (52.8 mg, 0.356 mmole), after which the reaction mixture was stirred at room temperature for 1.5 hours, at the end of which time thin layer chromatography (TLC) with 5% ethyl acetate in dichloromethane showed no iodocarbapenemstarting material remaining. The reaction mixture was concentrated in vacuo to give 222.1 mg of a reddish thick oil. The material was used without further treatment in the subsequent step of deblocking.

In 3 ml of dichloromethane and 2 ml of ethyl acetate there was dissolved the crude enantiomerically pure product of Example 3, 2-(4-pyrrolidinopyridiniummethyl-4-phenyl)carbapenem (5.) (about 0.310 mmole), and the solution was cooled undernitrogen atmosphere to 0.degree. C. A solid mixture of triphenylphosphine (24.4 mg, 0.093 mole) and tetrakis triphenylphosphinepalladium (35.8 mg, 0.031 mmole) was then added, followed by 2-ethylhexanoic acid (54.5 .mu.l, 0.341 mmole) and 0.5M potassium2-ethylhexanoate in ethyl acetate solution (682 .mu.1, 0.34 mmole). The reaction mixture was then stirred for 4.0 hours at room temperature, after which time the reaction slurry was diluted with diethyl ether and the solid product was collected bycentrifugation. The supernatant was decanted and the solid residue was washed three times with diethyl ether, after which the product was dried under high vacuum to yield 198.5 mg of a reddish solid. The crude reaction product was dissolved in aminimum volume of water, applied to three 500.mu. 20.times.20 cm silica gel reverse phase chromatography plates, and eluted with 30% tetrahydrofuran in water. The product bands were extracted six times with a 4:1 mixture of acetonitrile:water and thecombined aqueous extracts were washed three times with hexanes, after which the aqueous solution was filtered through a prewashed DR Gelman millipore filter and concentrated in vacuo, then lyophilized to give 84.6 mg of a slightly yellow solid.

Employing the procedures described above, additional compounds of the present invention were prepared. These are described in the table below, which additionally includes characterizing data and the method of preparation for each compound.